Transportation intermediaries or third party logistics companies (3PL) act as the facilitators to arrange the efficient and economical movement of goods. They serve tens of thousands of shippers and carriers, bringing together the transportation needs of the cargo interests with the corresponding capacity and special equipment offered by rail, motor, air, and ocean carriers. Transportation intermediaries play a key role in cross border transportation by land, sea, and air.

Traditionally, transportation intermediaries have been primarily non-asset based companies whose expertise is providing mode- and carrier-neutral transportation arrangements for shippers with the underlying asset owning and operating carriers. They get to know the details of a shipper's business, then tailor a package of transportation services, sometimes by various modes of transportation to meet those needs. Transportation intermediaries bring a targeted expertise to meet the shipper's transportation needs. Transportation intermediaries invest in sophisticated software that helps maximize logistics efficiency. Today, many also invest in physical assets such as trucks, aircraft, warehouses, and consolidation centers so that they can offer a fuller, vertically integrated range of service options.

Depending on the mode of transportation or the services offered, transportation intermediaries are called by a number of names. Transportation intermediaries involved in the trucking industry are licensed by the Federal Motor Carrier Safety Administration (FMCSA) of the United States Department of Transportation as either brokers or freight forwarders. Transportation intermediaries involved in ocean transportation are licensed by the Federal Maritime Commission to operate as either a Non Vessel Operating Common Carrier (NVOCC) or freight forwarder. Transportation intermediaries involved in airfreight must register as an indirect air carrier with the Transportation Security Administration (TSA). No license or authority is required to operate as an intermodal marketing company.
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